In operation since 1967, the large Nançay radio-telescope has a completely renovated electronics. It consists of a 200-metre-wide flat wire-mesh mirror, which can be rotated around a horizontal axis. This mirror reflects the celestial radio waves onto a fixed 300 m x 35 m mirror, which focuses them onto a mobile platform carrying the receivers. It is thus possible to follow the motion of a source of radio waves. The Large Radio-Telescope is used to measure the quantity of gas in distance galaxies, or to assess the gaseous emission of comets. It is also used for the study of pulsars, the very compact stars that emit radio waves as very regular pulses.
